A deadly outbreak of avian botulism in Waikato’s Whangamarino Wetland has killed thousands of birds, including some rare indigenous species.

Fish and Game New Zealand say it’s “yet another wake-up call for urgent action” to be taken by the Waikato Regional Council.

“The latest outbreak of the deadly bacteria, which produces a toxin that can paralyse and kill birds, follows multiple and increasing outbreaks during summers in and around the Waikato region over the past decade,” Fish and Game New Zealand said in a press release on its website.

Poor water quality and changes to water flows as a result of human activities contribute to low oxygen levels, creating the perfect growing conditions for this bacteria.

 “This results in fish dying, followed by birds before the botulism spreads to other surrounding wetland environments,” Fish and Game New Zealand said, calling it “yet another wake-up call for urgent action”.

The Whangamarino Wetland is the second-largest freshwater wetland in the North Island, covering almost 7000 hectares in Waikato, and was chosen as one of three nationally-significant wetland sites in the Department of Conservation’s Arawai Kākāriki wetlands restoration programme.

Fish and Game New Zealand chief executive Corina Jordan says the outbreak is an appalling situation and has had a massive impact on fish and bird populations in these wetlands.

“Parts of this wetland have been without oxygen for the best part of three months, leading to massive aquatic deaths of even the hardiest freshwater species such as eels. This isn’t normal in healthy freshwater wetland systems,” Jordan said.

Fish and Game New Zealand chief executive Corina Jordan. Photo / Fish and Game New Zealand

Jordan says the Waikato Regional Council needs to take a hard look at how the system is managed and limit discharges into these waterways to help decrease the likelihood and severity of these incidents continuing to occur in the future

“There have been long-term systemic failures in freshwater policies and a lack of implementation that has caused severe degradation in our freshwater ecosystems. Lake Waikare, one of the Southern Hemisphere’s most polluted lakes, has also been diverted into the wetland as part of the flood control scheme, which is adding even more nutrients to the wetland,” she said.

Degradation of waterways and associated environments, coupled with predictions of longer hotter summers, means these types of botulism outbreaks are likely to become more common, Jordan said.

Fish and Game New Zealand’s southern game bird manager for the Auckland and Waikato region, David Klee, says the situation is grim.

“Botulism is symptomatic of severely degraded ecosystems and this area is being adversely impacted by human activity to the point where its resilience is severely compromised,” Klee said.

Thousands of wetland birds have been killed by the recent outbreak of botulism. Photo / Fish and Game New Zealand

“Fish and Game, the Department of Conservation, Mana Whenua, and hunter volunteers, in conjunction with contractors, have recovered close to 1,500 dead birds and rescued hundreds of sick ones from the wetland, an important step in trying to minimise the size and scale of the outbreak.”

Klee says Fish and Game NZ is doing everything it can with the limited resources available, however, many parts of the wetland area, covering 7000ha, are inaccessible.

“It is an appalling situation both in terms of animal welfare and the environmental impact,” he said.

Ngāti Naho Trust CEO Haydn Solomon has been assisting in the clean-up operations and is concerned by the lack of action being taken.

“Our whānau want answers from authorities, not excuses. We are tired of the hui with consultants that lack follow-through, or hollow speeches from our leaders or mayors that go nowhere. Our waterways are getting hammered,” Solomon said.

“Our wetlands, lakes, rivers and springs are at breaking point, yet nothing substantive and meaningful is done.”